Reverberation chambers are used for generating statistically uniform and isotropic distributions of electromagnetic or acoustic energy within a test volume. In an electromagnetic reverberation chamber, the walls, ceiling and floor are generally metallic and highly reflective of electromagnetic energy. In an acoustic reverberation chamber, the walls, ceiling and floor are of a material such as concrete that is highly reflective to acoustic waves. The distribution of energy within a reverberation chamber is multimodal, with energy being transferred between modes as a consequence of reflective baffles or shaping of the room itself. Energy within the reverberation chamber may be stirred in three dimensions by a variety of methods including rotating reflective paddles or baffles, so that the stirred energy dominates the fields in the test volume. Also, variations can be obtained by rotating or moving the signal generating source or measuring device within the volume of the chamber.
FIG. 1 is a diagram of a typical electro-magnetic reverberation chamber 10 having a metallic floor 12, metallic ceiling 14, and four metallic sides 16 (only two sides shown) to enclose a device under test, DUT. In FIG. 1, a measurement antenna 20 may be mounted on a first positioner 21, and a calibration antenna 22 may be mounted on a second positioner 23. The positioners may be controlled by software and/or a user.
A line of sight, LOS, shield 24 may be mounted between the measurement antenna 20 and the calibration antenna 22. The LOS shield 24 may be metallic and used to block line of sight electric field components between the two antennas 20 and 22.
The reverberation chamber 10 may also include a horizontal z-fold tuner 26 and a vertical z-fold tuner 28. The z-fold tuners 26 and 28 may be made of large aluminum reflecting sheets supported on either a rigid box frame or a single spine and designed to provide the efficient reflecting surfaces desirable for use in the reverberation chamber 10. In particular, at one end of the vertical z-fold tuner 28 is pulley wheel 30 which rotates antenna 20 at a fixed ratio with respect to the vertical z-fold tuner 28.